With wide application of intelligent terminals (smart phones) and machine-to-machine (M2M) communication, a growing quantity of small data packets are being transmitted, especially in fields such as smart metering, intelligent transportation, and smart healthcare that are supported by M2M services. Data transmission of the small data packets is regular to an extent. For example, a relatively small amount of data is transmitted each time, and a time interval for data transmission is relatively long. In a Long Term Evolution (LTE) system, data transmission of user equipment (UE) is performed based on scheduling by a base station. To improve resource sending efficiency, UEs in a connected mode may share one or more resources. UEs in an idle mode may share a resource pool.
UE receives, on a downlink physical hybrid automatic repeat request indicator channel (PHICH), feedback information of uplink data sent by the UE, and a PHICH resource is determined based on uplink sending resource information and demodulation reference signal (DMRS) information of the UE. In the LTE system, the base station allocates one DMRS to a plurality of UEs. Therefore, when UEs that have a same DMRS select a same uplink resource, a downlink feedback channel of the UE is not uniquely determined. A plurality of UEs may receive feedback information on a resource of a same PHICH channel at the same time.
In an existing solution, all UEs send, on a fixed downlink feedback resource, feedback information that carries an identity of the UE. However, because the feedback information is carried on the fixed resource, a quantity of UEs that support simultaneous feedback is limited when few resources are reserved, and a resource waste is caused when a lot of resources are reserved.
In another existing solution, a group of UEs in a connected mode are configured, to share one uplink sending resource or a group of uplink sending resources. Feedback information of the group of UEs forms a bitmap. Each UE determines a location of feedback information of the UE in the bitmap based on identification information of the UE, and determines a downlink PHICH resource based on the uplink resource and feedback resource group information. There is no mechanism for determining a PHICH resource by idle UE, and distinguishing between feedback information of different UEs.
It can be learned from the foregoing that in the prior art, a quantity of UEs cannot be flexibly supported while resource utilization is ensured. In the prior art, feedback information of different idle UEs cannot be distinguished from each other.